Matrix Multiplication

This week I am going to teach you all how to multiply matrices. The bigger the two matrices are, the longer it takes to multiply them. There are a few things you need to know before you multiply matrices.

Notes:
• To be able to multiply matrices, the inner numbers of the two dimensions have to match. For example 2x3 3x2; you would be able to multiply these two matrices. Ex. 4x3 2x4; you would not be able to multiply these two matrices because the middle numbers are not the same (if this happens your answer will be not defined).
• The dimensions of the answer will be the outer two numbers. For example, 4x3 3x4; the dimensions of the answer would be 4x4.
• You multiply each row by each column
Now I will work an example of a matrix multiplication problem.

Example: [4 5] x [6
.............................3]
• First you would check the dimensions: 1x2 2x1; the resulting matrix will be a 1x1
• Next you would multiply 4 (6) + 5 (3)
• Your answer would be [39]

-Braxton